Transformer coil winding device



April 30, 1940. H. M. SANDERS TRANSFORMER COIL WINDING DEVICE Filed Dec. 20, 1938 6 Sheets-Sheet 1 e d N Tn e oa W t w fii .v A Wm WM H April 1940- H. M. SANDERS 2.199.116

TRANSFORMER GOIL WINDING DEVICE Filed Dec. 20, 1938 6 Sheets-Sheet 2 Fig. 8.

I' Inventor: Horn er- M. Sanders,

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April 1940- H. M. SANDERS 2,199,116

TRANSFORMER COIL WINDING DEVICE Filed Dec. 20, 1938 6 Sheets-Sheet 3 Fig. 6.

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TRANSFORMER coIL wninme DEVICE Filed Dec. 20, 1938 6 Sheets-Sheet 4 ficav: HQWWQT" M. anrag To W 1/ w J I April 30, 1940. SANDERS 2,199,116

TRANSFORMER COIL WINDING DEVICE Filed Dec. 20, 1938 6 Sheets-Sheet 5 P P J-n\ W i Fig. lb.

Inventor: Homer- M. Sanders His Attorne g.

April 30, 1940. H. M. SANDERS TRANSFORMER COIL WINDING DEVICE Filed Dec. 20, 1938 6 Sheets-Sheet 6 Fig I5.

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His Attornep Patented 'Apr. 30, 1940 UNITED STATES TRANSFORMER con. WINDING DEVICE Homer M. Sanders, Sharon, Pa., assignor to General Electric Company, a corporation of New York Application December 20, 1938, Serial No. 246,865

6 Claims.

This application is a continuation-in-part of my copending application Serial No. 186,895, filed January 25, 1938, and assigned to the same assignee as the present application.

' My invention relates in general to inductive electrical apparatus having continuous magnetic circuits, and particularly to electrical transformers, and the method of producing the same, and important objects of the invention are, to improve the electrical and magnetic circuits of continuous core inductive electrical apparatus; to facilitate the assembly of the laminations constituting the magnetic circuits; and to apply the coils and insulation constituting the electrical 15 circuits in proper relation to the assembled cores.

It is a further important object of the present invention to provide magnetic and electrical circuits of reduced weight and improved performance as compared to known transformers or the like apparatus of equal ratings.

It is also an object of the present invention to provide a novel method of assembling laminations from continuous steel strip rolled into a closed magnetic loop or core, and to provide facilities for application of the coils and the insulation of the electrical circuit within the symmetrical closed magnetic loops thus formed.

Another important object of the present invention is to simplify the structure and shape of ,the laminations constituting the magnetic cirao cuit, and to eliminate excess material, labor and equipment required by present methods of core formation and application of coils and insulation.

Still another object of my invention is to provide an improved method and apparatus for applying electrical conductors and insulation to permanently closed magnetic circuits.

Other important objects of my invention will be apparent from a reading of the following de- 0 scription taken in connection with the drawings, wherein for purposes of illustration I have shown preferred embodiments of my invention.

In the drawings, Fig. 1 is a plan view of a transformer assembly produced in accordance with the present invention; Fig. 2 isa transverse vertical sectional view, enlarged, taken through Fig. 1 approximately on the line 2--2 and looking toward the left in the direction of the arrows; Fig. 3 is an enlarged transverse vertical sectional 50 view taken through Fig. 1 approximately on the line 33; Fig. 4 is a plan view of one of the steel strips used in forming the continuous loop cores, and showing a portion of uniform width, merging into portions of tapering width at weld points, 5 the grain running lengthwise in the said strip;

Fig. 5 is an enlarged transverse vertical sectional view taken through Fig. 6 approximately on the line 5-5; Fig. 6 is a side or end elevational view of one of the loop cores'showing the manner in which the same is spirally wound and showing its appearance afterbeing pressed into the required shape; Fig. '7 is an end or side elevational view of a press employed in pressing the loop cores after winding, to assume the oval or rectangular shape illustrated in Fig. 6; Fig. 8 is a m transverse vertical sectional view taken through Fig. 7 approximately on the line 8-8 and looking toward the right in the direction of the arrows; Fig. 9 is a longitudinal sectional view taken through the combined core section mounting dem vice and coil winder, and showing a core section in place therein; Fig. 10 is a transverse vertical sectional view taken through Fig. 9 approximately on the line Ill-l0 and looking toward the right in the direction of the arrows; Fig. 11 is a fragmentary detail transverse vertical sectional view taken through Fig. 9 approximately on the line ll-| I; Fig. 12 is an 'end-elevational view looking from right to left in Fig. 9; Fig. 13 is a longitudinal sectional view corresponding to Fig. 9 representing a modification in the arrangement of Fig. 9; Fig. 14 is a transverse vertical sectional view taken through Fig. 13 approximately on the line i l-44 and looking to the right in the direction of the arrows; Fig. l5 is an end elevational view looking from right to left in Fig. 13; and Fig. 16 is an enlarged fragmentary detail view of the apparatus of Figs. 13 and 14, seen from the end.

Referring in detail to the drawings, it will be apparent that in accordance with the present invention any desired core section may be produced, but for purposes of illustration, a polygonal-shaped core section, which gives the maximum cross section area for a given enclosing circle is shown. Strips of tapered width and strips of uniform width are employed selectively in proper combination to produce the desired core section. A strip of uniform width throughout its length will form a rectangular or square core section, while a polygonal-shaped core section, such as that shown herein, requires the utilization of two tapered elements designated I and 3, respectively, and one element designated 2, which is of uniform width, joined together in end to end relationship to form one continuous strip, with the grain of the metal running longitudinally. The resulting taper is not great, as will be understood from consideration of the final shape of the core section to be achieved, but this taper is gradual as indicated in Fig. l of the drawings.

In forming a magnetic core by the method of the present invention, the strips I, 2 and 8 of magnetic steel are Joined together by welding and then wound into an annular form of the required dimensions, by first passing the cold strip through a solid dielectric, of low melting point, such as parafllne, while said dielectric is in its liquid state so as to form a film on the cold strip, and so as to separate the resulting laminations and provide a lubricant to facilitate the process of formation, and then to place the coiled v strip in a press such as shown in Fig. 7 of the drawings, to press and form into a rectangular shape. It is then placed in an annealing frame, also represented by the device shown in Fig. 7 of the drawings, to support it during the annealing of the formed cores.

At the beginning of the annealing process the dielectric of low melting point is drained off for re-use, and this draining off produces a space for expansion in annealing and produces a space between the laminations when the form cools, for reception of a film of penetrating and hardening dielectric to fiow between the laminations, so that in the same operation it is made possible to reduce the hysteresis losses by removing elastic stresses in the molecular structure, and to reduce eddy current losses by separating the laminations with dielectric 3.

After the formed cores have been finished and tested, they are assembled and held together by suitable devices (not shown) such. as clamps or steel wires, to maintain the symmetry of the leg or core on which the coils are to be applied. When the core section is clamped in the combined core section mounting device and winding device illustrated in Figs. 9 through 12, the core section is ready for application of the coils and insulation 4, by means of the collapsible winding form l3 which comprises the segments 5 banded together with wire i0 lying in circumferential grooves II, the segments 5 being tongue and groove connected as shown in Fig. 1.0.

The segments 5 have rack teeth 1' formed at their opposite ends which form a. circular rack l2 which is operatively engaged by the spur gears or pinions 1 which are fixedly mounted on the rotatable rods 8, the rotation of which produces rotation of the coil winding form I3.

The rotatable rods 6 are equally radially spaced from a stationary shaft 5' which is supported by passing through the stationary support 8 and the adJustablesupport 8', alongside of the rods 6 which turn in the elements 8 and 8'. Mounted on the righthand end of the shaft 5 is the idler gear 6 which is meshed with the pinions 8 which are fastened to the projecting ends of the shafts 8, whereby all of the shafts 6 are rotated at the same speed when a crank or other rotating mechanism is applied to any one of the shafts 6, for rotating the coil form [3 at the desired speed and in the desired direction. As shown in Fig. 9 of the drawings, the support 8 is stationary with the base l5 and this base is provided with a pair of tracks ifilwith which slidably engage the openings in the lower part of' the adjustable support element 8, which part of the support 8' is equipped with a clamping bolt 11 to be turned down against the top of the base to lock the support element 8' in the adjusted position on the base, suitable to accommodate the length of the core sections and coil forms to be wound. Of course, the stops I8 on the shaft 8' and I! on the shafts 8 are provided with clamping bolts 2ll'and 2!, respectively, to enable adjustment of the stops along the respective shafts to accommodate the adjustment of the support 8'.

0n the facing sides of the respective supports 4 8 and 8' and arranged in number and position in accordance with the number and arrange- I ment of the core sections to be mounted and wound, are the holding blocks 22 which slide between pairs of guides 23 and are held in position by adjustable bolts 24 which are threaded in lugs 25 on the sides of the support elements, the working faces of the blocks 22 being shaped to conform generally with the portion of the core sections to be engaged. In the present instance, three of the arrangements just described are provided to accommodate the three core sections employed in the illustrated example, and these are equally circumferentially spaced and will be I adjusted to the blocks 22 to be at equal radial the wires III are cut and withdrawn, so as to permit removal of the winding drum segments 5. When the segments are removed, the insulated fillers 28 and 21 are put into place between the formed coil 28 and the radially inward and radially outward surfaces of the inner opening of the core section and the opposite ends of the coil 28 as indicated by the numerals 29 and 38, whereby the coil including its insulation envelope 4 and the respective core section designated 3| are assembled. Owing to the fact that the core strip material is tapered, the core section 3| of the core has the shape of a geometric figure, the sides of which are slanting or inclined so that, as shown in Fig. l, the cores may be fitted closely together in order to obtain a high space factor of the magnetic material, that is, so as to make the cross sectional area of the core material a relatively high fraction of the cross sectional area of the opening or window in the conductive winding structure or coil 28. The necessary wedges 32 are then installed between the inner periphery of the coil 28 and the two adjacent core sections as illustrated in Figs. 1 and 3 of the drawings. Figs. 2 and 3 show particularly the arrangement of the fillers. It is to be noted that the segments 5 forming the winding form l3 have slots I2 cut in the ends thereof and opening into the grooves l I to facilitate cutting of the wires l0 therein in the operation of collapsing the winding form.

In the present general transformer practice followed by all manufacturers, the magnetic circuit consists of I, L or E-shaped laminations punched or sheared from large sheets of metal assembled in various forms with both single and at least one, and in most cases there are two to four breaks in each individual lamination circuit, each adding to the total reluctance of the path. 1

By the use of continuous core loops or sections each wound from continuous strips, these joints are eliminated as well as other undesirable features, and it is made possible to use cylindrical coils which provide the shortest mean turn of copper and a more perfect winding with greater facility. Absence of these Joints also eliminates magnetic hum or noise. Furthermore, the loops can be annealed and core loss tests made before applying the coils and insulation, thereby assuring uniform performance within close limits. The composite result of these provisions is a reduction in size, weight, and losses for a given core, coil and insulation combination, affording the designer a means of maintaining performance with an appreciable reduction in size and weight and a more symmetrical, uniform and rugged product.

Obviously, for a given core section and coil space, the weight of iron, copper, and insulation is reduced appreciably, and waste encountered in customary practice is entirely eliminated. Expensive dies or special equipment for stamping or cutting laminations are not required in the present invention, and it is, therefore, possible to use laminations of maximum thickness within the limits imposed by eddy current conditions and maximum content of elements such as silicon or nickel for improvement of magnetic properties. Furthermore, it is possible to gain satisfactory results with less material or better results with the same material heretofore used for a given rating. The time saved in core assembly more .than compensates for any extra time required for coil and insulation application. Also, the coils may be removed and rewound without dismantling the core in case of trouble requiring repairs.

The combined forming clamp and annealing frame shown in Figs. '7 and 8 comprises essentially the top and bottom members 35 and 36 which are connected by the clamping rods 31 and 38 which are adjustable to produce the desired clamping action against the, ends of the core section, the core section in its annular form being designated by the numeral 3i in Fig. 7, wherein it is shown in dotted lines. Between the elements 35 and 36 are the elements 39 and 40 which are traversed by clamping rods ll and 42 which like the clamping rods 3l'and 38 are arranged in pairs on opposite sides of the core section, with the pairs of rods 4i and 42 located outside of the pairs of clamping rods 31 and 38, as shown in Fig. 7 of the drawings. The dotted lines designated 3| show the final shape-of the core section as affected by the proper operation of the clamping rods.

Although in Fig. 9 I have shown an arrangement for driving and supporting the coil winding form from the inside, it will be understood that my invention is not limited to this specific arrangement and obviously includes driving and supporting the coil winding wound from the outside. For example, as shown in the arrangement of Figs. 13 and 14 I may utilize a winding form flanged portions carrying teeth i2a, such that when the segments are assembled they form a flanged spool or reel, the flanges of which form gears.

The gear teeth l2a are operatively engaged by the pinions Ia which are fixedly mounted on the I3a composed of segments 511 having rotatable rods 8a, the motion of which produce rotation of the coil winding form l3a.

The rotatable rods 80. are equally radially spaced from a stationary shaft 8 which is supported by passing through the stationary support 8 alongside of the rods to which turn in the elements 8 and 8. Mounted on the right hand end of the shaft 5' is the idler gear 8' which is meshed with the pinions 9a which are fastened to the projecting ends of the shafts 6a, whereby all of the shafts 8a are rotated at the same speed when a crank or other rotating mechanism is applied to any one of the shafts to for rotating the coil form l3a at the desired speed and in the desired direction.

Although I have shown and described herein preferred embodiments of the invention, as a transformer, and as apparatus for producing the same, and as a procedure for achieving such a. transformer, it is to be definitely understood that I do not desire to limit the application of the invention thereto, but any change or changes may be made in the materials and in the structure and arrangement of parts, as well as in the sequence and duration of operation concerned, within the spirit of the invention and the scope of the subjoined claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a base, a pair of standards thereon, a shaft extending between the standards, paired core section holders on the facing sides of said standards arranged at circumferen tially spaced intervals around said shaft and adapted to support closed loop core sections disposed between said standards in radial positions with their radially inward sides closely adjacent said shaft, a rotatable coil form surrounding said shaft and adapted to pass through core sections supported in said holders, and means rotatably supporting said coil form.

2. In combination, a base, a pair of standards thereon, a/shaft extending between the standards, paired core section holders on the facing sides of said standards arranged at circumferentially spaced intervals around said shaft and adapted to support closed loop core sections disposed between said standards in radial positions with their radially inward sides closely adjacent said shaft, a rotatable coil form surrounding said I shaft and adapted to pass through core sections supported in said holders, and means rotatably supporting said coil form, said coil form being sectional in character.

3. In combination, a base, a pair of standards thereon, a shaft extending between the standards, paired core section holders on the facing sides of said standards arranged at circumferentially spaced intervals around said shaft and adapted to support closed loop core sections disposed between said standards in radial positions with their radially inward sides closely adjacent said shaft, a rotatable coil form surrounding said shaft and adapted to pass through core sections supported in said holders, and means rotatably supporting said coil form, said coil form being sectional in character, and said means comprising additional rotatable shafts on said standards operatively engaged with said coil form.

4. In combination, a base, a pair of standards thereon, paired core section holders on the facing sides of said standards adapted to support a closed loop core section between said standards, a rotatable coil form adapted to pass through a core supported in said holders, and means rotatably supporting said coil form, one of said standards being slidabie along the base in a direction parallel to the axis of rotation of the coil form.

5. In combination, a base, a pair of standards thereon, paired core section holders on the facing sides of said standards adapted to support a closed loop core section between said standards, a rotatable coil form adapted to pass through a core supported in said holders, and means rotat ably supporting said coil form, said coil form being sectional in character with notched ends to form gear teeth for rotatably driving said coil form.

comprising rotatable shafts on said standards 10 carrying pinions operatively-engaged with said coil form.

HOMER M. SANDERS. 

